Numerous situations exist in which a body cavity needs to be catheterized to achieve a desired medical goal. One relatively common situation is to provide nutritional solutions or medicines directly into the stomach or intestines. A stoma is formed in the stomach or intestinal wall and a catheter is placed through the stoma. This surgical opening and/or the procedure to create the opening is commonly referred to as “gastrostomy”. Feeding solutions can be injected through the catheter to provide nutrients directly to the stomach or intestines (known as enteral feeding). A variety of different catheters intended for enteral feeding have been developed over the years, including some having a “low profile” relative to the portion of the catheter which sits on a patient's skin, as well as those having the more traditional or non-low profile configuration. These percutaneous transconduit catheters (sometimes referred to as “percutaneous transconduit tubes”) are frequently referred to as “gastrostomy catheters”, “percutaneous gastrostomy catheters”, “PEG catheters” or “enteral feeding catheters”. U.S. Pat. No. 6,019,746 for a “Low Profile Balloon Feeding Device” issued to Picha et al. on Feb. 1, 2000, provides an example of one device.
A problem universal to low profile and non-low profile enteral feeding devices or enteral feeding assemblies (e.g., gastrostomy tubes) is the difficulty in inserting a retainer in a body lumen to hold the enteral feeding assembly in a fixed position in the lumen. Balloons have been used, which are deflated for insertion through the stoma and then inflated to hold the enteral feeding assembly in position. While balloons have many advantages, balloon may eventually leak and deflate. Other retaining fixtures have been difficult to insert through a stoma, and often must be endoscopically placed by a physician, usually during a surgical procedure. These retaining fixtures are typically made of the same silicone composition used to make the enteral feeding device and are frequently molded as part of the device. The end which is inserted into a body lumen may have a Malecot tip consisting of three or four generally semicircular loops of material which radiate from the end of the tube and join at a tip. The radial loop sections can seat against the interior stomach wall so as to impede the inadvertent withdrawal of the tube. Liquid nutrient passes from the tube into the stomach through the openings between these semicircular loops. Examples of conventional devices with Malecot tips or similar expanding tips are found at, for example, U.S. Pat. No. 3,915,171 for “Gastrostomy Tube” issued to Shermeta; U.S. Pat. No. 4,315,513 for “Gastrostomy and Other Percutaneous Transport Tubes” issued to Nawash et al.; U.S. Pat. No. 4,944,732 for “Gastrostomy Port” issued to Russo; and U.S. Pat. No. 5,484,420 for “Retention Bolsters for Percutaneous Catheters” issued to Russo. Exemplary commercial products include the Passport® Low Profile Gastrostomy Device available from Cook Medical, Inc. of Bloomington, Ind. and the Mini One™ Non-Balloon Button available from Applied Medical Technology, Inc. of Brecksville, Ohio.
A shortcoming of these devices relates to the manner of insertion and withdrawal of a catheter or tube incorporating these retaining fixtures (e.g., a gastrostomy tube) into a body lumen such as into the stomach. As generally illustrated in FIG. 1, this is typically accomplished by a surgeon who inserts a stylet 100 through the length of the tube 105 and up against the end of the Malecot tip or similar expanding tip 110 while gripping the device 115 at its base 120. Referring now to FIG. 2, as the surgeon pushes the stylet 100 and tube 105 through the abdominal wall opening, the force of the end of the stylet 100 elongates the entire device 120 from about the base 115 to the tube 105 and the Malecot tip or similar expanding tip 110, thereby stretching and/or pulling the semicircular sections into a straight, elongated configuration (or stretching and/or pulling the similar expanding tip into an elongated configuration). When so elongated, the Malecot tip (or similar expanding tip) can pass through a gastrostomy opening into the stomach. When the stylus then is withdrawn, the resiliency of the tube material pulls the elongated sections of the Malecot tip back into semicircular configuration (or allows the similar expanding tip to retract to its expanded configuration), thereby securing the end within the stomach.
In practice, both the tube and the Malecot tip or similar expanding tip stretch which require providing much greater length of the article being inserted through a gastrostomy opening. This elongation of both the tube and the Malecot tip or similar expanding tip also makes withdrawal of the device more difficult because the stylet must be inserted further into the body. This presents difficulties for smaller patients, particularly for children and babies. In addition, much greater force is required to extend both the tube and the Malecot tip or similar expanding tip. The greater travel of the stylet into the body in combination with greater force applied to the stylet creates more potential for harm if the stylet is not aligned properly on the Malecot tip or similar expanding tip, if the stylet slips off the tip or if the tip fails and separates from the tube.
Accordingly, there is a need for an enteral feeding assembly and associated insertion device(s) which permits a user or health care provider to quickly and easily insert the assembly, including the retainer, externally through the patient's stoma and into a body lumen, such as, for example, a stomach lumen. Such an assembly and retainer are desirably configured so that during insertion, the retainer has an outer diameter which is about the same as the outer diameter of the portion of the catheter which extends into the stoma. However, after insertion, it is desirable that the outer diameter of the retainer expands to hold the enteral feeding assembly in the desired position for enteral feeding. Moreover, it is desirable to have a retainer that may be expanded in a body lumen without inflation. Finally, it is desirable that any devices used to insert, expand, contract, and/or remove the retainer be simple and easy to use.